Uninitialized variables: Fixed false positives when goto is simplified and inner condition is known to be true/false
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548a43fc49
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@ -1088,6 +1088,9 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const unsigned int
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unsigned int number_of_if = 0;
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// variables that are known to be non-zero
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std::set<unsigned int> notzero;
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for (; tok; tok = tok->next()) {
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// End of scope..
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if (tok->str() == "}") {
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@ -1109,12 +1112,20 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const unsigned int
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continue;
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}
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// assignment with nonzero constant..
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if (Token::Match(tok, "[;{}] %var% = - %var% ;") && tok->next()->varId() > 0)
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notzero.insert(tok->next()->varId());
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// Inner scope..
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if (Token::simpleMatch(tok, "if (")) {
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// initialization / usage in condition..
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if (checkIfForWhileHead(tok->next(), varid, ispointer, suppressErrors, bool(number_of_if == 0)))
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return true;
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// checking if a not-zero variable is zero => bail out
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if (Token::Match(tok, "if ( %var% )") && notzero.find(tok->tokAt(2)->varId()) != notzero.end())
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return true; // this scope is not fully analysed => return true
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// goto the {
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tok = tok->next()->link()->next();
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@ -1889,6 +1889,17 @@ private:
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"}\n");
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TODO_ASSERT_EQUALS("error", "", errout.str());
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// if goto is simplified there might be conditions that are always true
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checkUninitVar2("void f() {\n"
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" int i;\n"
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" if (x) {\n"
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" int y = -ENOMEM;\n"
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" if (y != 0) return;\n"
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" i++;\n"
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" }\n"
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"}\n");
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ASSERT_EQUALS("", errout.str());
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// for, while
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checkUninitVar2("void f() {\n"
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" int x;\n"
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